Camo Man

Hi, for a 2001 Chevy S-10 pickup. While driving exhaust started getting louder. And was kind of stalling a bit with the rpms going up and down some while at a steady speed. Then needed to give it more gas to maintain the speed. And rpms kept going up more as the speed went down. Drove a bit to house and then was very high rpms to get only slow speed.
Oil level is good. When got home opened hood and it was smoking a bit. Gauges were good also. Exhaust had gotten a tad louder a while ago. And did notice a bit of 'stalling' and up and down when driving once in a while for a while before this.
Ideas what this might be?